The present invention relates to electrical power supply circuits using a solar generator as a source and including a battery. Such a circuit has a particularly important, but non-exclusive, application in the field of artificial satellites placed in low earth orbit (LEO). Such satellites pass periodically into the shadow of the earth, in general once on each revolution, thereby making their solar generators ineffective.
On-board electrical power supply circuits already exist on satellites that comprise a solar generator made up of a plurality of sections that are individually connectable to a power busbar by means of switches, together with a storage battery and a smoothing capacitor.
In that known circuit, the supply of electricity from the solar generator to the power busbar is controlled by a sequentially switched regulator operating with a limiting on/off cycle. A cycle of one of the sections being alternately put into and then out operation of service takes place for as long as the solar generator is capable of maintaining a reference voltage on the busbar. In contrast, the means enabling the battery to discharge to the power busbar comprise linear servo-controlled regulator means so as to maintain the voltage on the power busbar at a determined voltage while it is the battery that is powering the busbar. The circuit also has a filtering capacitor of small capacitance (capacitance of about one millifarad), serving to keep voltage variations on the power busbar down to a small value, where said variations are due to solar generator sections being switched, and serving as an energy storage device for the chopper regulator associated with the battery. Since the amount of energy stored by such a capacitor is very small, the cycle of connecting and disconnecting the busbar and the solar generator is short. Consequently, the switch means and the regulator must operate at high frequencies, thereby making it necessary to use high performance components, i.e. components which are therefore complex and expensive.